Stock pusher and locator



June 23, 1970 D L. cooPER 3,516,316

STOCK PUSHER AND LOCATOR Filed April 1o. 196s United States Patent O 3,516,316 STOCK PUSHER AND LOCATOR Donald L. Cooper, Hamilton, Ohio, assignor to Continental Can Company, Inc., New York, NY., a corporation of New York Filed Apr. 10, 1968, Ser. No. 720,217 Int. Cl. B26d 7/16 U.S. Cl. 83-419 11 Claims ABSTRACT OF THE DISCLOSURE A pivotally mounted stock pusher fixedly secured to a punch press stripper plate by a mounting bracket. The bracket is positioned so that lowering of the upper movable die shoe of the press causes the pusher to come into contact with, and slide upon the top surface of the lower stationary die block. In so doing, the pusher engages, pushes, and positively locates the stock or workpiece within the punch press.

This invention relates to stock pushers for use with metal punching, shaping, forming or drawing presses and more particularly, to a stock pusher that is actuable by the downward motion of the upper die shoe of the press.

Traditionally, workpiece stock has been manually inserted into a press and positioned against gauges or stop blocks located on the top surface of the lower die or on the lower die shoe. This manual placement and positioning requires considerable care to insure proper positioning of the workpiece beneath a punch. That is to say, unless the press operator exercises great care, the stock will bounce away from the stops and be improperly positioned on the lower die block.

To overcome the difficulties of manual placement and positioning, stock pushers or crowders are now commercially available. These pushers, however, have met with limited commercial acceptance because of their construction, location and operation. Speciiically, these pushers are objectionable because they incorporate components or parts iixedly secured to the lower die shoe of the press in a position to obstruct insertion of a workpiece into the machine so that the press operator must lift the workpiece or stock over a part of the pusher assembly in order to position it adjacent the stop blocks. Additionally, these commercially available pushers have a tendency to raise the stock with respect to the lower die block and die shoe during a pushing or crowding operation and thus cause the stock to become mislocated at the critical moment just prior to punch engagement,

It has therefore been one objective of this invention to provide a stock pusher which moves upwardly with the press ram when the ram is raised so as to present an open area for unencumbered insertion and removal of stock into and out of the press.

Another objective of this invention has been to provide a stock pusher which securely holds the stock once it has positioned it beneath the press ram.

It has been a further objective of this invention to provide a stock pusher which repeatedly effects correct positioning of the stock in the press.

The stock pusher of this invention accomplishes these objectives. It comprises a spring biased pusher pawl which is pivotally mounted to a yoke shaped bracket attached to the stripper plate. The pivot for the pawl is preferably resiliently mounted with respect to the bracket so as to accommodate variances in the sizes of the workpieces.

When the upper die shoe of the press is raised, this stock pusher presents an unobstructed area through which rice stock may be inserted and removed. Downward motion of the upper die shoe causes the pawl of the pusher to contact and slide upon the top of the lower die block, thereby eifecting pivoting of the pawl, and pushing of the stock against the stop blocks on the lower die of the press. The stock pusher is then operative to maintain a steady force against the stock during the continued downward stroke of the upper die shoe so as to insure contact of the stock with the stop blocks or gauges until and after the cutting or shaping operation is completed.

These and other objectives will become more apparent when considering the following detailed description taken in conjunction with the drawings in which:

FIG. l is a vertical cross sectional view of a punch press employing the stock pusher of this invention, the upper die shoe of the press being shown in a raised position;

FIG. 2 is a view similar to FIG. l but showing the upper die shoe and punch of the press in a lowered position and the stock pusher in the attitude it assumes during a punching operation; and

FIG. 3 is a top plane view of the stock pusher taken along lines 3-3 of FlG. 2.

Referring to the drawings, the stock pusher `14 is illustrated as applied to a punch press which comprises an upper movable die shoe 11, an attached pressure plate or stripper plate 12, and a lower, stationary die shoe 13. A punch is fixedly secured to the lower side 16 of the upper die shoe 11 by a conventional punch mounting block 17. The tool 15 secured to the upper die shoe has been illustrated as a punch but it could as well be a conventional forming, shaping, or drawing die without departing from the spirit of this invention.

The stripper plate 12 is resiliently suspended from the upper die shoe 11 by stripper plate mounting bolts 21. Each bolt 21 is slidably received in a counterbored hole 22 of the upper die shoe 11 and has a head 23 which seats upon an annular shoulder 24 of the hole when the shoe 11 is in a raised position. The shank 25 of each bolt 21 passes through a small diameter section 26 of the hole 22 and is threaded at its lower end, the threaded section 27 being threaded into a threaded aperture of the stripper plate. The threaded section 27 is smaller in diameter than the shank of each bolt so as to provide a shoulder 28 which seats upon the top surface 30 of the stripper plate 12. A compression spring 31 surrounds the shank 25 of each bolt between the ram head 11 and stripper plate 12 so as to bias the stripper plate downwardly away from the upper die shoe.

The stationary lower die shoe 13 is fixedly secured to a base (not shown) of the press and supports a stationary lower or bottom female die block 32. Fixedly mounted in an aperture 36 of the lower die 32 is a workpiece stop gauge or block 34. A portion or head of this gauge extends upwardly above the plane of the top surface 37 of the lower die so as to form a stop for determining the rearward extent of insertion of a workpiece into the press, or in other words, to position the rear edge 38 of a workpiece 39 on the die block 32. To locate a workpiece laterally on the die block 32, a pair of positioning pins or guides extend upwardly above the plane of the top surface 37 of the die 32.

For purposes of this description, two stock pushers 14 have been illustrated as applied to the stripper plate 12 to position a single workpiece 39 against the stop blocks or gauges 34. There could be a greater or lesser number of pushers i4, depending upon the size and conguration of the workpiece.

Each stock pusher 14 comprises a yoke shaped bracket pivotally supporting a pusher pawl 54 in a pair of parallel arms #t6-46. Each arm 46 has a mounting ange 47 secured to the vertical side edge 49 of the stripper plate 12. An apertured rubber grommet 51 is mounted within an aperture in each arm near the outermost end 50 of the arm 46. Each grommet 51 supports one end of a pusher pawl support pin 52. A bridle or strap 53 interconnects the top edges of the arms 46-46.

Each pawl support pin 52, intermediate its ends, pivotally supports one end of the pusher pawl 54. As may be seen in FIG. 1, a torsion spring 55 surrounds the pin 52 and has one arm 56 biased against the lower surface 57 of the bridle 53 and the other end 58 hooked over the top surface of the pawl 54 so that the inner or camming end of the pawl is biased downwardly. Engagement of the top surface of the pawl with the bridle 53 limits downward movement of the inner end of the pawl to a position in which the pawl extends at an angle of approximately 30 to a horizontal plane.

OPERATION Assuming the press to be in the condition as depicted in FIG. 1, and the upper die shoe 11 to be raised, the press is in a position for insertion of a new workpiece. After the workpiece 39 is inserted onto the top of the die 32, it will be in the position illustrated in FIG. 1 with the rear edge 38 located against or near the stop gauges 34, depending upon the care of the operator in inserting the workpiece. The press is then activated to lower the upper die shoe 11 and the attached stripper plate 12 and pusher 14. Lowering of these components causes the cam surface 57 of tthe pusher pawl 54 to come into contact with and slide along the top surface 37 of the die 32, thereby imparting a clockwise rotation to the pawl against the bias of the spring 55.

Upon continued lowering of the upper shoe 11, edge 57 of the pawl 54 cornes into contact with the workpiece or stock 39 and pushes the stock against the stops. Continued downward movement of the upper shoe 11 results in engagement of the bottom surface of the stripper plate with the top surface of the workpiece. The workpiece is thus locked in position between the bottom surface of the stripper plate and the top surface 37 of the lower die 32. Upon continued downward movement of the upper die shoe 11, the stripper plate is supported by the lower die block 32 while the punch 15 and shoe 11 continue to move downwardly, thereby compressing the stripper plate springs 31 as the punch or die 15 engages and punches a blank from the workpiece. The blank then falls through the aperture 33 in the die 32 and a colinear aperture in the lower die shoe 13.

Upon upward movement of the upper shoe 11, the stripper plate 12 holds the workpiece 39 in engagement with the top surface 37 of the die 13 while the punch 15 is withdrawn from the aperture in the workpiece. Upon continued upward movement of the shoe 11, the stripper plate moves upwardly with the die shoe 11 after the heads 23 of the bolts 21 engage the shoulders 24 of the apertures 22 in the upper die shoe 11. When the die shoe 11 is in its fully raised position, the stripper plate and the pusher pawl are both disengaged from the workpiece, as illustrated in FIG. 1, so that the workpiece may be removed from the press and a new workpiece inserted.

The primary advantage of the pusher heretofore described over prior art pushers is that it accurately locates a workpiece against stops or gauges and then securely holds the workpiece during the punching, shaping or forming operations. It also has the advantage over pushers heretofore commercially available of not obstructing insertion of a workpiece into the press and into a position on top of the lower die shoe. In other words, all of the pusher parts, other than the stop gauges, are attached to the stripper plate so that they move upwardly out of a position of interference with the insertion and removal of a workpiece.

While only a single preferred embodiment of the invention has been described herein, those persons skilled in the arts to which this invention pertains will readily appreciate numerous changes and modifications which may be made without departing from the spirit of my invention. Specifically, those persons skilled in this art will readily appreciate that this stock pusher could be utilized in other press applications, as for example, workpiece forming or shaping operations. Additionally, other configurations and adaptations of workpiece pusher pawls or toggles could be substituted for the pawl illustrated herein. Therefore, I do not intend to be limited except by the scope of the appended claims.

Having described my invention I claim:

1. A stock pusher for use in combination with a press having a movable upper die shoe, a stationary lower die shoe, a stripper plate resilently suspended from said upper die shoe, and a die block xedly mounted upon said lower die shoe, said die block having stop gauges extending upwardly from the top surface thereof to locate a workpiece on said block, said stock pusher comprising a pusher element having one end suspended from said stripper plate, and

cam means on the opposite end of said pusher element engageable with said die block, said cam means being operative upon downward movement of said stripper plate and pusher element to engage said die block and effect movement of said opposite end of said pusher element toward said stop gauges on said die block so as to move a workpiece supported upon said die block into engagement with said stop gauges.

2. A stock pusher for use in combination with a press naving a movable upper die shoe, a stationary lower die shoe, a stripper plate resilently suspended from said upper die shoe, and a die block xedly mounted upon said lower die shoe, said die block having stop gauges extending upwardly from the top surface thereof to locate a workpiece on said block, said stock pusher comprismg a pusher element having one end suspended from said stripper plate, and

cam means on the opposite end of said pusher element engageable with said die block, said cam means being operative upon downward movement of said stripper plate and pusher element to engage said die block and effect movement of said opposite end of said pusher element into engagement with a workpiece on said die block and toward said stop gauges so as to move said workpiece into engagement with said stop gauges.

3. The stock pusher of claim 2 wherein said pusher element is pivotally supported at said one end upon said stripper plate.

4. The stock pusher of claim 3 wherein said pusher element extends angularly downwardly from said pivotal support toward said stop gauges and forms an acute angle with a vertical plane through said pivotal support.

5. A stock pusher and die 'block for use in combination with a press having a movable upper die shoe, a stationary lower die shoe, and a stripper plate resilently suspended from said upper die shoe, said die block having stop gauges extending upwardly from the top surface thereof, said stop gauges being adapted to locate a workpiece on said block when said block is xedly mounted upon said lower die shoe of said press,

a stock pusher including a pusher element, said pusher element having one end adapted to be suspended from said stripper plate, and

cam means on the opposite end of said pusher element engageable with said die block, said cam means being operative upon downward movement of said stripper plate and pusher element to engage said die block and effect movement of said opposite end of said pusher element toward said stop gauges on said die 'block so as to move a workpiece supported upon said die block into engagement with said stop gauges.

6. The stock pusher of claim 5 wherein said pusher element is pivotally supported at said one end upon said stripper plate.

7. The stock pusher of claim 6 `wherein said pusher element extends angularly downwardly from said pivotal support toward said stop gauges and forms an acute angle with a vertical plane through said pivotal support.

8. A stock pusher for use in combination with a press having a movable upper die shoe, a stationary lower die shoe, a stripper plate resiliently suspended from said upper die shoe, and a die block xedly mounted upon said lower die shoe, said die block having stop gauges extending upwardly from the top surface thereof to locate a workpiece on said block, said stock pusher comprising a support bracket adapted to be tixedly secured to said stripper plate,

a pusher element having one end pivotally supported in said bracket, said pusher element being adapted to slope downwardly from said pivotal support at an acute angle to a horizontal plane through the bottom of said stripper plate when said pusher is mounted upon said stripper plate, the slope of said angle being generally directed from said pivotal support toward a workpiece located upon said die block, and

cam means on the opposite end of said pusher element engageable with said die block, said cam means being operative upon downward movement of said stripper plate and pusher element to engage said die block and effect pivotal movement of said opposite end of said pusher element toward said stop gauges on said die block so as to move a workpiece supported upon said die block into engagement with said stop gauges.

9. The stock pusher of claim 8 wherein said opposite end of said pusher element is spring biased downwardly.

10. The stock pusher of claim 8 wherein said pusher element is pivotally supported in resilient elements so as to enable said pusher to accommodate slight dimensional variances in workpieces.

11. In combination with a press having a movable upper die shoe, a stationary lower die shoe, a stripper plate resiliently suspended from said upper die shoe, and a die block Xedly mounted upon said lower die shoe, said die block having stop gauges extending upwardly from the top surface thereof to locate a workpiece on said block, a stock pusher comprising a support bracket adapted to be xedly secured to said stripper plate,

a pusher element having one end pivotally supported in said bracket, said pusher element normally sloping downwardly from said pivotal support at an acute angle to a horizontal plane through the bottom of said stripper plate, the slope of said angle being generally directed from said pivotal support toward a workpiece located upon said die block, and

cam means on the opposite end of said pusher element engageable with said die block, said cam means being operative upon downward movement of said stripper plate and pusher element to engage said die block and effect pivotal movement of said opposite end of said pusher element toward said stop gauges on said die blocks so as to move a workpiece supported upon said die block into engagement with said stop gauges.

References Cited UNITED STATES PATENTS WILLIAMS. LAWSON, Primary Examiner U.S. Cl. X.R. 83-467 UNITED STATES PATENT OFFICE CERTIFICATE OF CGRRECTION Patent No. 3 l516 316 Dated June 23 1970 Inventor(s) Donald L. Cooper It is certified that error appears in the aboveidentified patent and that said Letters Patent are hereby corrected as shown below:

Column l ,i line 3 through line 5 please delete "assgnor to Continental Can Company, Inc. New York, N Y. a corporation of New York".

:suin'mw SEALED 001201@ (SEAL) '"1' new mmm E. m, Edward MFletch, I?. @Missionar of Patenti;

Anesting Officer 

